Electrical conductor



' of station wires and cables.

Patented May 25, 1943 ELECTRICAL CONDUCTOR Julius A. sum-d, name, N. Y.,assignor to General Cable Corporation, New York, N. Y., a .cor-

lmration of New Jersey Application August 3, 1940, Serial No. 350,459.-

19 Claims. (Cl. 174-421) This invention relates to mold-proof androtproof non-metallic coverings, particularly those adapted for use asinsulating and protecting jackets for electrical conductors, and theinvention has for its principal object the improvement'of suchconductors as well as the insulating and protective jackets therefor.

For a long time there has been a great need for a low cost substancesuitablefor use in saturants and finishers for non-metallic conductorjackets or sheaths which will be highly resistant to mold (fungusgrowthlas well as to rotting (decomposition in presence of bacteria) andwhich will blend readily with the saturants and finishers withoutaffecting their properties in general and their resistance to weatheringand aging in particular.

From a practical angle rotting is, as a rule, more dangerous because itmay completely destroy th outer'coverin'gs of a cable. Cases are knownwhere in barns, stables and other similar places the entire outercoverings of nonmetallic sheathed cables rotted away in a relativelyshort time. These outer coverings frequently consists of cotton braid,saturated and finished with asphalt and stearin pitch compounds,overlying folded kraft paper armor treated with parafiin. .At times onlythe cotton braid rotted away, but in more severe cases even the paperarmor and the paper or cotton braid, which is below it, became rotten.In some cases there was a very definite mold growth on the surface ofthe rotten outer cove gs.

Mold growth" without rot quently in warm damp-places like the conduitsin power houses and substations, where no decaying organic matter ispresent. Thismay be ob served on either the dry or the saturated braidsThe mold may be only on the surface, in which case it is comparativelyharmless, or it may penetrate below the finishing coat and slowlydestroy the cotton braid. It is this latter type of mold growth whichmay cause serious damage to cables. If

permitted to go unchecked, it may destroy the.

entire outer coverings.

Furthermore, electrical conductors are required to be made fiameandfire-resistant, which is customarily accomplished by saturating orcoating one or more of the fibrous jackets or coverings with a stearinpitch compound.

One of the principal aims and objects of the present invention is theprovision, of an inexpensive compound which may be used alone, or

many non-metallic sheathed occurs frecombined with customarily usedmoisture-proofing saturants or flame-resistant finishing -cornpounds,and which will be highly eiiective as a mold and rot inhibitor for usein non-metallic sheathed electrical cables.

According tothe present invention, this need is satisfied by the use ofthe'still residue of diphenyl-oxide distillation containing phenoliccompounds, including alkali metal phenolates. This tarry residue may beused alone, or combined with customary asphaltic saturants, as asaturant for insulating bodies, or it may be compounded with customarystearin pitch finishing compounds. This still residue is inexpensive ofuse and highly eiiective as a mold and rot inhibitor-sin electricalcables.

A specific embodiment of the invention comprehends the use of the tarryresidue obtained during the distillation of 'diphenyl-oxide as a moldand rot inhibitor on the fibrous Jackets or coverings of electricalcables which may be sub- Ject to mold or rot. This tarry residue hasbeen known for some time, but-has been considered a waste material. Sofar as I know, it has never been used or suggested for use heretofore asa I 7 CcHaCcI-l's.

In addition it contains water soluble alkali metal salts of phenolicmaterials, mostly sodium salts like sodium phenolate, CcHsONa, sodiumortho-phenyl phenolate CsHmGsHANfl and others. These alkali metal saltsamount to about 20% of the total. These are water soluble and since acertain water solubility is required for effective fungicidal andgermicidal action against fungi and bacteria occurring on wet or dampplaces, these sodium salts and notably sodium phenolate represent themost active ingredient of this still residue. I

This still residue is a dark colored tarry compound, with propertiessimilar to a bituminous compound. It is tacky at room temperature, butis quite brittle at low temperature. It melts at C. and is quite fluidat -100 C.

At,100- C. it impregnates cotton and other fibrous materials readily.Its flash point is at 145 C. and its fire point at 165 C. Like a greatnumber of bituminous compounds, this still residue has a certain amountof cold flow. It also has a certain oil resistance. When ignited itburns readily, but has some tendency to 'coke. This permits its use instearine pitch base bituminouscompounds which have fiame resistance dueto their choking properties. This still residue may vvary somewhat inphysical properties depending on the distillation process, but the abovecharacteristics are typical.

As a compound for use in the manufacture of electrical cables theprincipal virtues of this still residue are its excellent mold and rotresisting properties; its impregnating qualities for cotton, itscompatibility with moistureproof asphalt saturants, its compatibilitywith flame and moisture resistant stearine pitch compounds and finallyits low cost.

Theinvention may be embodied in the manufacture of electrical cable in avariety of ways,

depending upon the use to which the cable is to be put. For example, itmay be used alone as a saturant for cotton, jute or other fibrous layersin the interior of the cable structure where adhesion between layers isdesired. It can not be used alone on the outside of the cable unless acable. I have found that this still residue may 4 be combined with anyof the saturating compounds in amounts of 1550%. The addition of thisstill residue will make these saturants rot and mold resistant.

Due to its oil resistance this still residue does not readily blend withsome of the more viscous petroleum asphalts. I found that in such casesthe addition of 5-10% of montan wax or rosin helps to form a homogeneousblend of asphalt and still residue.

A second group of saturants' used in'the cable industry are known asflame retardant compounds; these are based on stearine pitch because ofthe good coking properties of this material. Stearine pitch too, isblended with montan wax, petroleum waxes or other modifying agents andis used in this modified form. I

stearine pitch compounds with the still residue.

In addition to the saturating compounds the cable industry uses hardfinishing compounds over the saturants to improve appearance and thehandling properties of the cable. These finishers usually have a meltingpoint range of 180-220" F. anda penetration at 77 F. of 4-10.

These are either mixtures of petroleum asphalts or. native asphalts likegilsonite with waxes like montan, paraffin, etc., or they are based onstearine pitch modified with native asphalt and waxes.

I ha"e found that this still residue may be combined with either type upto 10-25% and that the addition of this still residue will make eithertype of finisher rot and mold resistant.

The following is an example of a rot and mold resistantalso flame andmoisture resistant finisher:

' Pounds Hard stearine pitch F. M. P.) 45 Gilsonite 25 Montan wax r 10Still residue 10 Paraflin 10 For all types of fibrous coverings,jackets, wrappings, felts or braids which are used on cables and may besubject to attack by mold, rot,

termites and the like, the use of saturants and finishers containingthis still residue will give protection against rot, mold, termites andthe like. I

Illustrative of the wide range of uses of the invention, reference ismade to the accompanying drawing showing several forms of conductorembodying the invention, in which: p

Fig. 1 is a side view of one form of non-metallic covered conductorembodying the invention;

Fig. 2 is a similar view of a modified form thereof;

Fig. 3 is a side view of a non-metallic sheathed cable constructionembodyingthe invention; and

Fig. 4 is a side view of one form of underground cable embodying myinvention.

In the variousvfigures the outer coverings are cut away successively 'toshow the structure underneath, and the numeral l0 represents the core,which may be solid or stranded, and II the'insulation thereover, whichmay be a rubber compound, synthetic resin or saturated fibrousinsulating material.

In the construction shown in Fig. 1, the insulation ll may be providedwith an overlying non-metallic jacket 12, subject to attack by mold,

10% to 25% of the still residue provides a smooth, non-sticky; moldandrot-resistant finish for the cable.

'Instead of incorporating the fungicide with the finish coating, as inFig. 1, it may be mixed with the saturant, either an asphalticmoistureproof saturant or a flame-resistant stearin pitch, asillustrated in Fig. 2. In such cases up to 15% to 30% of the stillresidue may be mixed with the saturant l3 to render the jacket I2moldand rot-resistant.

In the form of invention shown in Fig. 3, a plurality of insulatedconductors I0 may be individually covered with a paper-cotton braid asat I 5 and enclosed in a protective tape wrapping, for example paper.The assembled conductors are enclosed by a paper dam i6 and an overlyingnonmetallic fibrous jacket 11 which is subject to attack by rot andmold. The braid Il may be provided with a. conventional saturant, suchas a fireand moisture-resistant stearin pitch and with a coat offinisher containing from 10% to 25% of the still residue. Alternatively,'the saturant for jacket I! may be compounded with 15% to 50% stillresidue'as'in the case of the cable shown in- Hg. 2, in'which case thefinish coat may be of any convenient type.

In the case oi. imderground cables, illustrated in Fig. 4,.the insulatedconductor it may be wrapped or braided with cotton, jute, sisal or otherfibres it, which may be saturatedas at II with the still residue whentackiness is not objectionable, or with a mixture of bituminouscompounds containing from 15% to 50% of the still residue. Also it isfeasible to presaturate the cotton, jute, sisal or other fibres andapply the presaturated fibres to the cable.

I have found that the inclusion of still residue inthefinisher of fromto 25%, or in the saturating compound of from to 50%, produces aconductor which not only withstands mold growth and is perfectlypreserved after four weeks of incubation at C. seeded with chaetomiumglobosum, but in which the cost of saturating and finishing the braid issubstantially reduced due tothe cheapness of the still residue ascompared with the cost of the usual saturating and finishing materials.

I am aware that heretofore many mold and rot inhibitors have been knownand used, or suggested for use, for proofing textile and fibrous bodies,such as sulphur and copper salts and aldehydes. The cost of using thesematerials, however, was prohibitive except'where it was possible to useinexpensive residual coal tar compounds which hav good moldandrot-resistance and which may be used in certain underground cableconstruction. However, for non-metallic sheathed electrical conductors,coal tar compounds cannot be'used because these compounds are notflame-resistant, do not age well above ground and cannot be mixed wellwith customary stearin pitch finishing compounds.

The insulated conductor constructions shown sulated conducting core. amold and rot resistant sulated conducting core and a mold and rotresistant fibrous jacket therefor saturated with the phenolic tarryresidue of diphenyl oxide distillation.

2. An electrical conductor comprising an insulated conducting core and amold and rot resistant fibrous jacket therefor saturated with alatedconducting core and a mold and rot resistant fibrous jacket thereforsaturated with a moisture-resistant and flame-resistant stearine pitchbase saturant containing 15% to 30% of the phenolic residue of diphenyloxide distillation.

5. An electrical conductor comprising an insulated conducting core and afibrous jacket therefor saturated with a moisture-resistant aridflame-resistant stearine pitch base saturantcontaining 3% to 6% ofsodium phenolate. contained in the residue of diphenyl oxidedistillation and mixed in this form with the stearinic pitch of thesaturant to render the fibrous jacket .mold and rot resistant.

'6. An electrical conductor'comprising an infibrous jacket and. a finishcoating therefor of in the drawings are merely illustrative of thevarious applications of the invention, and it will be understood thatthe phenolic compound containing an active sodium salt of phenol, forexample the still residue hereinabove described, may be used alone, orcombined with the saturant and waxes in desired proportions, dependingupon the particular use for which the cable is intended.

As sodium phenolate is one of the active ingredients of the stillresidue similar results can be obtained by mixing sodium phenolate withthe various saturants and finishers. However, since it is easier andcheaper to blend the still residue. which is a bituminous material withsimilar bituminous compounds than it is to mix pure sodium phenolat-ewith the bituminous compounds I prefer to use the still residue which inaddition is much lower in cost than equivalent amounts of sodiumphenolate would be.-

It is customary when saturating fibrous materials with bituminouscompounds to keep the 'emperature below 350-400 F. because above thattemperature the strength of the fibrous material is adversely aiiectedby the high temperature. This holds true for the saturating compoundscontaining the still residue; these should therefore not b used assaturants over 400 F.

It should be also noted that both the saturant and finisher may containthe still residue.

It will be undestood that the invention may be variously embodied withinthe limits of the prior art and the scope of the subjoined claims.

I claim: I

1. An electrical conductor comprising an in- 25% of the phenolic tarryan asphalt-wax base finisher containing 10% to residue of diphenyl oxidedistillation. a I

'1. An electrical conductor comprising an insulated conducting core, afibrous jacket and a finish coating therefor of an asphalt-wax basefinisher containing 2% to 5% of sodium phenolate contained in'theresidue of diphenyl oxide distillation and combined in this-form withthe asphalt wax used in the finisher to render the finisher mold and rotresistant.

8. A mold-resistant and rot-resistant electrical conductor comprising aconducting core and a fibrous jacket therefor treated with the phenolictarry residue of diphenyl oxide distillation.

9. A mold-resistant and rot-resistant electrical conductor comprising aconducting core and a fibrous jacket therefor treated with a. stillresidue jacket of an electrical conductor comprising the phenolic tarryresidue of diphenyl oxide distillation.

11. A saturant for rendering moisture-resistant, mold-resistant androt-resistant the fibrous protective jacket of an electrical conductorcomprising an asphalt base and 15-50% Y of the phenolic tarry residue ofdiphenyl oxide in this form with the asphaltic materials of said base. aI

13. A saturant for rendering flameand moisture-resistant and also'moldand rot-resistant the fibrous protective jacket of an electricalconductor comprising a stearine pitch base containing 15-30% of thephenolic tarry residue of diphenyl oxide distillation blended with thestearine pitch base by 53-10% of rosin or montan wax.

14. A saturant for rendering fiameand moisture-resistant and alsomoldand rot-resistant the fibrous protective jacket of an electricalconductor comprising a stearine pitch base combined with 3-6% of sodiumphenolate contained in the residue of diphenyl oxide distillation andmixed in this form with the stearinic pitch materials of said base.

15. A finisher for rendering moldand rotresistant the fibrous protectivejacket of an electrical conductor comprising an asphalt-wax basecontaining 10-25% of the-phenolic tarry residue of diphenyl oxidedistillation blended with the asphalt-wax base by 5-10% of montan wax.

16. A finisher for rendering moldand rotresistant the fibrous protectivejacket of an electrical conductor comprising an asphalt-wax basecombined with 2-5% of sodium phenolate contained in the residue ofdiphenyl oxide distillation and mixed in this form with the asphaltwaxmaterials. of said base.

17. A finisher for rendering fiameand moisture-resistant and alsomoldand rot-resistant the fibrous protective jacket of an electricalconductor comprising a stearine pitch base containing 10-25% of thephenolic tarry residue of diphenyl oxide distillation blended with thestearine pitch base by 5-10% of montan wax.

18. A finisher for rendering fiameand moisture-resistant and alsomoldand rot-resistant the fibrous protective jacket of an electricalconductor comprising a stearine pitch base combined with 2-5% of sodiumphenolate contained in the residue of diphenyl oxide distillation andmixed in this form with the stearinic pitch materials of said base.

19. A treating material for rendering fibrous materials mold-resistantand rot-resistant comprising the phenolic tarry residue of diphenyloxide distillation.

JULIUS A. SZILARD.

I CERTIFICATE OF CORRECTION. Patent No. 2,520,201. May 25, 1915.

.mmus A. SZILARD.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 8, for "choking" read -'-cokingline 35, for '2O-5O."read --20-hO.--; and that the said Letters Patent should be read withthis correction therein that the same z nay conform to the record of thecase in the Patent Office.

Signed and sealed this 29th day of June, A. 1).. 1915.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

. Patent No. 2,320,201 May 25, 19!;5.

JULIUS A. SZILARD.

It is hereby certified that err-er appears in the printed speeificetionof the above numbered patent requiring correction as follows: Page 2,first co1umn,'1ine 8, for "choking" read --coking-; line 55, for-"20-50.read I 20-1|.O.--- and that the said Letters Patent should be read withthis correction therein that the same may conform to the record of thecase in the Patent Office Signed and sealed this, 29th day of June, A.n; 1915.

,Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

